Although the presence of a linear fracture involving the cranial vault is very often of no slinical significance, the same is not true of fracture of the base. The authors analyzed 160 cases of basal skull fracture treated in the department of Neurosurgery, presbyterian Medical center from May 1980 to Apr 1985. Clinical features and radiological findings were reviewed, analyzed and correlated each other. The result of the analysis are summarized as follow : 1) The basal skull fractures were more common in man than woman the ratio of 13:3. 2) Clinical features were otorrhea(61.2%), racoon eye(22.5%), and hearing loss(20%) etc in decreasing order. 3) Combined pathologies were skull fracture(45%), subdural hematoma(13.7%), epidural hematoma(11.2%), and pneumocephalus(10%) etc. in decreasing order. 4) The facial nerve, vestibulo-cochlear nerve, and olfactory nerve were most common cranial nerves injured. 5) Among the visible fractures in simple X-ray, longitudinal fractures were more common than transverse fractures. 6) CSF leakage were noted in 126 cases, and among them immediate type was far more common(93.6%) than delayed type. 7) Incidence of meningitis was 5%, and most of them were associated with CSF leakage. 8) The infection rate was higher when the CSF leak persisted over 7 days.